Telephone system.



R. 1. QUASS. TELEPHONE SYSTEM.

APPLICATION FILED IVIIAY I. 1914..

Patented D0014, 1915.

2 smears-sun 1.

v, NW EM u be mL W W/ R AIL l V/fnesses:

- RALIPH IA'QTJ'ASS, OF NEW YORK, IN. "SC, ASSIGNOB T "WESTERN ELEC'IIRIC COMPANY,

' OF NEW YORK, N. 35,, A CORPORATION OF ILLINOIS.

' cise, and exact description.

TELEPHQNE SYSTEM.

Specification of Letters Patent. Patented Dec. 1%, 1915.

Application filed May 1, 191a. Seria1 no. 835,750.

-York, in the county of Bronx and State of New York, have 'inventeda certain new and useful Improvement 1n Telephone Saystems, of which the following s a full, clear, con- This invention relates to: telephone sys tems, and more particularlyto such systems foruse in inter-connecting central oflices at which terminate a plurality of telephone.

lines. 7

The object of this'invention is the production of improved signaling means for such telephone systems.

In accordance with one feature of this invention, a two-way trunk circuit is provided, with means at each end for automatically applying ringing current to the trunk circuit for a definite period, for operating a signal at the other end of the circuit upon connecting the link conductors with the trunk circuit.

This invention will he more fully understood by reference to the drawings showing one embodiment of the invention, in which all apparatus is shown in its normal and unactuated condition, and wherein,--

Figure l'shows a subscribers line terminating at a central office, and link conductors and a portion of a trunk circuit at the central office; and Fig. 2 shows a subscribers line terminating at another centralofiice, and line conductors and a portion of the above mentioned trunk circuit thereat, the conductors of the trunk circuit being joined to connect the two central offices.

'In' thev drawings there are shown sub- -vscribersstations A and B terminating at central I ofiices C and .1) respectively. A trunk circuit E joins the two central oliices, at each of which is shown a. cord circuit. It

' is believed that this invention will be fully understood from a description of the operation of the system shown in the drawings,

and it will be so described.

It will be assumed that subscriber A will be furthermore assumed that A has sigthat the wanted line is that of subscriber B terminating at another central oiiice D. The operator at U thereupon inserts the calling plug of the cord circuit into jack .5 of the desires to converse with subscriber B, and it trunk circuit E joining the central oiiices C and D, completing a circuit fromthe live pole of batteryb through supervisory sig" nal 7, winding of relay 8, over conductor 9, sleeve contacts 10 and 11 of the calling plug and the jack 5, conductor 12, and through the winding of-relay 13 to ground. Current in this path operates the supervisory. signal 7 and actuates relays 13 and 8, which latter relay in operating disconnects the operators telephone set from the talking strands of the cord circuit, and completes a circuit from the live pole of battery 20 through the winding of relay 21, normally closed contacts 22 of relay 23, and 2% of relay 25, and normally open Contact 26 (now closed) of relay 8 to ground. Current in this path actuates relay 21, completing a circuit for a source of ringing current 28 through the winding of ringing relay 25, normally open contact 29 (now closed) of relay 21, ring contacts 30 and 31 of the calling plug and the jack 5, conductor 32, winding of low resistance relay 33, normally closed contact 3% of relay 35, conductor 36,

tip contacts 37 and 38 of the jack 5 and the and release relay 21, which establishes the continuity of the talking strands of the cord circuit. Relay 33 in operating completes two circuits, the first from live pole of battery 42, through the winding of quick-operating and slow-releasing relay 1-3, conductor 4t, and normally open contact (now closed) of relay 33 to ground. Current in this path actuates relay e3, completing a circuit for a source of ringing current as through, normally open contact at? (now closed) of relay't3, conductors t8 and 4:9, normally closed contacts of relay 51, condenser 52, a winding of relay 53, conductors 54s and 55, and normally open contact 56 (now closed) of relay 43 to ground. Current in this path actuates relay 53 which locks up over a circuit from the live pole of battery 60, through a winding of-relay 53, normally open contact 61 (now closed) of relay 53, and normallylclosed contact 62 of relay 51 to ground. Actuation of relay 53 also completes two other circuits, one from the live pole of battery 63, through signal mally open contacts 69 and 70. At the time of completing a circuit through relay 43, a circuit Was also completed from the live pole of battery 74,- through a winding of relay 35, normally closed contact 75 thereof, conductor 44, and normally open contact 45 (now-closed) of slow-operating relay 33 to,

ground. Current in this path actuates relay 35, completing a locking circuit-therefor from battery 7 4, through a winding of relay 35, normally open contact 76 (now closed) thereof, conductor 77, and normally open contact 78 (now closed) of relay 13 to ground. Relay 35 in operating breaks the circuit of slow-release relay 33, which releases arid breaks the circuit of relay. 43. Relay 43 in releasing disconnects the source of ringing current 46 from the conductors of the trunk circuit. Actuation of relay 35 also closes normally open contact 79 in a section of the talking circuit.

It will be noted that through the quick: operating feature of relay 43, the slow-opcrating. feature of relay 35, the slow-releasing feature of relay 33, and the slow-releasing feature of relay 43, these relays when actuated coiipera'te to maintain the source of ringing current 46 connected to conductor 48 of the trunk circuit for a definite period of time, which insures the operation of signal 64 at the central ofiice D.

The operator at central office D observing the signal 64, inserts her answering plug of the cord circuit into jack 85 of the trunk circuit, completing a circuit from battery 86 through signal 87, normally closed contact 88 of relay 89, winding of relay 90, conductor 91, sleeve contacts 92 and 93 of the anwering plug and the jack 85, conductor 94 and winding of relay 51 to ground. Current in this path operates signal 87, actuates relay 90, placing the operators telephone set across the talking strands 95 and 96 of the cord circuit, and actuates relay 51. Actuation of relay 5]. completes a circuit from the live pole of battery 97, through a winding of relay 98, normally open contact 99 (now closed) of relay 51, conductors 49, 48 and 100, normally open contact 101 (now closed) of relay 13, winding of relay 105, conductors 106, 55 and 54, the other winding of relay 98, and normally open contact 107 (now closed) of relay 51 to ground. Current in this path actuates relay 105, closing. normally open contact 108 in a section of the talking circuit, and relay 98 closing normally open contact 109 in another section of the talking circuit. Closure of contact 108 completes .a

circuit Ham the live pole of battery 110,

through the winding of supervisory relay 111, ring contacts 30 and 31 of the calling plug and the jack 5, conductor 32, contacts 108 and 79, conductor 36, tip contacts 37 and 38 of the jack 5 and thecalling plug, and conductor 112 to ground, actuating relay 111 and eflacing the supervisory signal 7 by placing a low resistance shunt 115 about it. Similarly, closure of contact 109 completes a circuit from the live pole of battery 116, through the winding of supervisory relay 117, ring contacts 118 and ing .plug and the jack 85, conductor 120, contacts 109 and70, conductor 121, and tip contacts 122 and 123'of thejack 85 and the answering plug to ground, actuating relay 117 and effacing the supervisory signal 87 by placing a low-resistance shunt 124 about it.

A condenser 125 is shunted about relay 98 to provide a path for the talking current.

After inserting the answering plug of the cord circuit at central office D into the jack 85, the operator inquires of subscriber A the desired number, and finding it to be that of subscriber B, completes the connection in the usual manner. The operators telephone set at central oflice D is. removed from the talking strands of the cord circuit thereat in a manner similar to that described for central oflice C, and theapplication of ringing current to the called subscribers line is likewise accomplishedin a similar manner. The ringing current is removed from the called subscribers line by the removal of the re ceiver from. the switchhook at B, which completes a path of low resistance for the ringing current, and actuates a ringing relay in the cord circuit, this relay and other apparatus associated therewith functioning in exactly the same manner as that described in the cord circuit .at central office C.

When the conversation between the two connected subscribers is concluded, the subscribers restore the receivers to theswitchhooks, which opens the circuits from batteries 110 and 116 over subscribers lines A and B, respectively, permitting the operation of supervisory signal 130 in the answering end of the cord at central office C, and

supervisory signal 131 in the calling end of leases relays 105 and 98. Release of relay 98 opens the circuit from battery 116 through supervisory relay 117, which releases and operates supervisory signal 87. Both signals 87. and 131, being operated, act as disconnect signals to the operator at the central 119 of the answeroffice D. This operator now withdraws both plugs of the cord, thereby permitting all ap-t paratus to be restored to normal condition.

The system embodying this invention has been described as'operating in one direction, It is to be understood'that the trunk circuit is adapted to function properly when a call originates at either end. To this end both ends of the trunk circuit are similarly equipped, a signal 135,- condensers 132 and 133, and relay 136 at central ofiice C, corresponding to the signal 64, the condensers 52 and 125 and the relay 53 at central 'oilice D, also a slow-releasing relay 137, a quick-' operating and slow-releasing relay 138, and the slow-operating relay 66 at the central office D, corresponding respectively to-the relays 33, 43 and 35 at the central ofiice. C, and performing the same functions when a call-originates at the central ofiice D.

At both of the central oflices there is shown a plurality ofvbatteries, but these may be. combined into a single central battery at each office, and such is the usual practice. At each central office thereare shown two sources ofringing current, and likewise these may be combined into a single. source at each ofiice, such being the usual practice;

What is claimed is: v

1. A telephone system comprising sub scribers lines terminating .at a central office, link conductors thereat for interconnecting said lines, a source of ringing current at the central ofiice, a second central office, a signal thereat, a trunk circuit joining said offices, and slow-releasing and quick and slow-operating relays associated with said trunk circuit actuated and cooperating when said link conductors areconnected with said circuit to connect said ringing current to said circult for a definite period of time for operating said signal.

2. A telephone system comprising central Copies of this patent may be obtained for ofiices, subscribers lines terminating thereat and link conductors thereat for intercon nccting said lines, sources of ringing current and signals at saidofiices, a trunk circuit joiningsaid offices, and slow-releasing and quick and slow-operating relays associated with said trunk circuit actuated and cooperating when the calling end of a set of circuit for a definite period of time for op-' erating said signal at the other of said oflices.

3; .In .a telephone trunk circuit, a circuit it formed of main conductors, circuits at each end thereof formed: of auxiliary conduc-' tors, a signal and a plurality of switching devices included with said auxiliary cir- 'cui'ts, a source of control current and a sourceof ringing current included with said auxiliary circuits, a telephone exchange system at each end of the trunk circuit including link circuits adaptedto be connected with the trunk circuit, and means controlled by said switching devices rendered operative when a link circuit is connected with either end of the trunk circuit to complete a cycle of five successive operations, first, to interrupt the continuity of the main conductors, second, to include said ringing current with the main conductors, third, to operate the signal at the other end of, the trunkcircuit, fourth, to disconnect the ringing currrent from the main conductors, and fifth, to reestablish the continuity of said. main conductors. y

In witness whereof, I hereunto subscribe my name this 29 day of April, A. D., 191

RALPH L. QUASS.

\Vitnesses:

E, EDLER,

KATHERINE L. STAHL.

five cents each, by addressing the Commissioner of Patentswashington, D. C." 

